The invention discloses a microliter grade liquid injection control device. The control device uses the temperature gradient for controlling the pressure gradient; meanwhile, a gas-liquid phase changeprinciple technology is utilized, so that gas only forms liquid in a microliter grade container and always exists in a gas form in an inflating pipeline and a gas storage tank. In addition, the control on the liquid injection precision can also be realized by controlling the temperature of the gas storage tank; the goal of efficiently and precisely injecting a certain amount of liquid into the microliter grade container is finally achieved.